System of reaction control



n 9 J.-M. MILLER 1,787,950

SYSTEM OF REACTION coursox.

Filed Jui 23, 5

2 Sheets-Sheet 1 f1 ATTORNEY.

SYSTEM OF REACTION CONTROL Filed July 2.3, 1925 Z SheetS-Sheet 2 By 11,4 12(- cw 2 ATTORNEY.

Patented 6, 1931 -UNITED STATES PATENT OFFICE. A

MANUFACTURING COMPANY, OP OF PENNSYLVANIA JOHN M. MILLIB, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO ATWATER KENT PHILADELPHIA, PENNSYLVANIA, A CORPORATION SYSTEM OF REACTION- CONTROL Application flled July 28, 1925. Serial No. 45,481.

' My invention relates to the control, reduction or elimination of reaction'of one circuit or path upon another, particularly as regards high or radio frequency currents as utilized in sstems of radio communication or in high requenc carrier wave systems utilizing conductors etween stations.

In accordance with my invention, the reaction upon the input circuit of a three electrode thermionic device by disturbing electro-motive-forces in its anode circuit or in a.

. remote circuit is controlled, reduced or elimnected, respectively, to the point so defined and to the grid of the thermionic device.

Further in accordance with my invention, to avoid adjusting with nicetythe magnitudes of the'aforesaidinductances, or their relation-to each other, there is connected in parallel with either or both of the intra-tube capacities, existing between grid and plate and between grid and cathode a supplemental capacity of suitable magnitude.

My invention resides in a system of the character hereinafter described and claimed.

This application is in part a continuation of my prior application Serial No. 653,490, filed July 24, 1923.

For an understanding of my invention,

and for an illustration of some of the various forms it may take, reference may be had to the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of a circuit arrangement in accordance with my invention.

Fig. 2 is a diagram of a eatstone bridge circuit corresponding in general with the" circuit arrangement of Fig. 1.

Fig. 3 is a diagrammatic view of a. multistage amplifier having my invention applied to the individual stages thereof and between stages remote from each other.

Fig. 4 is a diagrammatic view of a further modification of my invention.

Fig. 5 is a diagram, in the form of a Wheatstone bridge, explanatory of that form of my invention illustrated in Fig. 4.

Fig. 6 is a fragmentary diagrammatic view of a further modification corresponding in general with Fig. 4.

Referring to Fig. 1, which is a. reproduction of Fig. 8 of my aforesaid application Serial No. 653,490, A and B are the terminals of or to which the input element is connected, or are the terminals between which the input energy or electro-motive-force is im&

pressed. The terminal A connects with .the grid G of the therminoic device VT, whose! anode or plate is indicated at P and whose filament or cathode is indicated at F. C and D are, respectively, the output' terminals or terminals in the anode circuit to which the output impedance or apparatus is connected.

The battery B1 snpplie current for heating the cathode F, and the battery B2 supplies the anode circuit energy.

Between a suitable point in the anode circuit, in which exist the disturbing electromotive-forces whose reaction upon the input system is to be controlled, reduced or elimihated, and the cathode F, are connected in series with each other the inductances L3 and L4, between which there is defined a point,.as 0, whose potential is different from that of the cathode F and at which the potential caused by the reaction of thedisturbing electro-motive-forces varies in phase with the potential of the anode P, or in general, in base with the disturbing electro motive orces. I The input energy is impressed ,between the point 0 and the grid G, that is, the terminals A and B of the input element are connected, respectively, to the point 0 and there is oflered substantially no reactance to the oscillations or undulating currents in- The arrangement of Fig. 1 is in effect a true Wheatstone bridge, as exemplified in Fig. 2. The input element, such as the circuit S, comprising the inductance L and the tuning con ser K, for tuning to the frequenc of the input energy, or any other suitab e or equivalent input element, is connected in that conjugate conductor of the bridge extending between the grid G and the aforesaid point 0. The capacity between the 'd,and cathode of the tube VT is indicate atCl, in one arm of the bridge, and in a corresponding arm of the bridge is the capaci C2 between the rid G and anode P of t e thermionic device. In the other arms of the brid e are the aforesaid inductances L3 and with the condenser C5 in series in the connection between the conjugate points P and F, connected, respectively, to the aforesaid terminals C and D between which may be connected the output impedance Z of any suitable type or character, as, for example, the primary of a transformer.

The resistance R and the source of fluctuating electro-motive-force E, indicated in dottc lines as connected between the points P and F, represent generically the internal resistance and electro-motive-force active within the tube VT in the anode circuit thereof. 7

The disturbing electro-motive-forces are in efiect impressed across the tube electrodes P and F, but their reaction upon the input element S, orequivalent, is nil when the bridge is in erfect balance, and are materially reduced mate balance.

As now well understood in the art, when the anode. circuitv of the thermionic device is to sufiicient extent inductively reactive, the

reaction upon the input system'is such as to in effect lessen its resistance, as by introduction of negative resistance, causing regenera- It will accordingly tive action, or in the extreme case the produetlon of osclllatlons. When the anodecircuit is capacitatively reactive or in effect contains only resistance, the reaction in efiect adds ositive resistance to the input system, decreasing the effective energy impressed upon the input system.

be understood that my system may utilized for controlling, reducing or-eliminatjn the reaction under any of the aforesaid con 'tions in the anode circuit. 1

' While the'bridge may be balanced by suitably relating to each other the magnitudes of the inductances L3 and L4, this is often of inconvenience, particularly in the production of radio receiving sets, in which it is desirable-to wind the inductance coils L3-and L ingreat numbers and relatively inexpenwhen the bridge is in approxi 'a mplifier stage, and between stages.

' mon sively, under which circumstances the magnitudes of these inductances will vary somewhat,'as will also their resistances due to lack of uniformity in the conductor. It is therefore simpler and cheaper to effect the balance or desired degree of balance of the bridge by recourse to the small condensers'cl and 02 connected in parallel with the intratube capacities C1 and C2, respectively. Either or both of the condensers 01 and 02 may be utilized, and a suitable magnitude for each is determined by trial for a given pair of inductances L3 and L4. I

In Fig. 3 there is shown a radio receiving system embodying my invention and comprising the antenna H, or equivalent absorption structure, between which and the earth or counter-capacity I is connected the primary J of an oscillation transformer whose, secondary is the inductance L of the input element S, shunted by the tuning condenser K. WVith the first stage vacuum tube VT, operating as a radio frequency amplifier, are associated the inductances L3, L4, condenser C5 and small condensers c1 and 02, as in Fig. 2. As indicated, one terminal of the cathode battery B1 maybe connected to earth or countercapacit I. The output impedance Z is coupled to t e primary L1, shunted by the tuning condenser K1, of the second stage input element S1, which impresses the amplified energy upon the second stage radio frequency amplifier VTl, with which are associated the inductances and condensers, as in the first :stage. The output impedance Z1 is inductively coupled to the in ut element S2 of a third stage, which may e that of a further radio frequency amplifier, or of a detector tu In the arrangement of Fig. 3 there is an additional structure for controlling, reducing or eliminating reaction of disturbing electromotive-forces of or in a remote point or stage,

as, for example, the input circuit of the third stage,'as illustrated, upon the input system of the first stage. .In my co-pending application Serial No. 145,539, filed November 1, 1926, there is described and claimed a similar balanced network for controlling the reaction between the input and output circuits o ig n 15 structure comprises an inductance L5 connected between the point 0 and a point at which exists a varying disturbing potential. When required, the stopping condenser C6,

of the character and purpose of the condenser C5, may be employed. In this instance the inductances L5 and L4 determine the point '0, which is simultaneously determined by the co-action of the inductances- L3 and L4. Wherethe inductance Ltis so utilizedin com- L5, the elimination or suitable reduction of ith two otherinductances, as L3 and the reaction by the remote disturbing electro-.

motive-force is eflected by suitably proportioningL to L for that remote disturbing electro-motive-force, in which case inductance L3 will partake of such magnitude with respect to the inductance L4 as to suitably reduce or eliminate the reaction of the adjacent disturbing electro-motive-force.

In Fig. 4 the point 0 is intermediate the terminals of the output impedance Z, and is connected in the conjugate conductor to the terminal B of the input element, as S or equivalent. In this connection of conjugate conductor there is provided a condenser C7, of large capacity, exhibiting very low reactance to the frequency of the current involved, to prevent impression upon the grid 7 G of the tube VT of the potential of thepositive pole of the anode circuit source B2. It will be understood that the condenser C7 may be disposed anywhere in the path between the point 0 and the grid G. Since in such an arrangement the grid G is insulated from the cathode F, there is utilized a high resistance R1 connecting the grid and cathode to each other. The second stage in this example comprises a detector tube VT2, in whose anode circuit is the instrument T, as a telephone, loud speaker, or the primary of lation transformer in this case, whose second-f ary is the inductance L1 in the input system of a succeeding stage.

In Fig. 6 an arrangement generally similar to that of Fig. 4 is shown. The point 0 is in this case, however, disposed intermediate the terminals of the secondary L1 of thetransformer whose primary is the impedance Z in the anode circuit of the tube VT. In order that the potential at the point 0 shall be in phase with the disturbing electro-motiveforce, that end of the inductance L1 which connects with the grid of the detector tube VI2, in whose anode circuit is the same source B2 and whose cathode is heated by current from the source B1, has the same polarity as that terminal of the impedanceZ which connects with the anode P of the tube VT. That is to say, the sense of winding or direction of connection of the secondary L1 shall be such that the polarity of its upper terminal shall at all times throughout successive oscillations be of the same polarity as the upper terminal" of the primary Z. l

For the purpose'of brevity, it shall be understood that the'term controlas employed in the appended claims is considered to in-' clude a degree of control at which the effect of a disturbing potential is eliminated.

What I claim is z 1. The combination with a three electrode thermionic device having an input circuit, an impedance connected between a point in said input circuit and the cathode of said thermionic device, a second impedance connected between said point and a point of disturbing potential remote from the input and out ut circuits of said thermionic device, an an input element connected between said first named point and the grid oii said thermionic device.

2. The combination with a three electrode thermionic device having an input circuit, an inductance connected between a point in said input circuit and the cathode of said ther: mionic device, a second inductance connected between said point and a point of disturbing potential remote from the input and output circuits of said thermionic device, a condenser of low reactance connected in series with said second inductance between said points, and an input element connected between said first named point and the grid of said thermionic device.

. 3. The combination with a three electrode thermionic device having an input circuit, an inductance connected between a point in said input circuit arid the cathode of said thermionic device, a second inductance connected between said point and a source of disturbing potential, a condenser of low reactance connected in series with said second inductance between said point and said source, and an input element having its terminals connected, respectively, to said point and the grid of said thermionic device.

4. The combination with a three electrode thermionic device having an input circuit,

an inductance connected between a point in said input circuit and the cathode of said thermionic device, a second inductance connected between said point and a point of disturbing potential in the anode circuit of said thermionic device, a. condenser having low reactance connected in series with said second inductance between said points, and an input element having its terminals connected, respectively, to said'first named point and the grid of said thermionic device.

5. The combination with a three electrode; thermionic device having an inptcircuit,

an impedance connected between a point in said"i nfiut circuit and the cathode of said thermionic device, a second impedance connected between said point and a point of disturbing potential remote from the input and outputrcircuits of said thermionic device, a

third impedance connected between said first named point and a point in the anode circuit of said thermionic device, and an inputelement connected between said first named point aid the grid of said thermionic a6;

. point and a point in the anode circuit of said' said a three-electrode thermionic tube, a

- cent said first arm,and im thermionic device, and an input element connected between said first named point and the gridof said thermionic device.

7. Ina radio receiving apparatus, a thermionic amplifier-having a grid, a plate and a. filament, a source of current connected with plate and filament, an input couplin trans ormer having a primary and a secon ary winding, a connection between said plate and filament including a fixedcondenser and an inductor coil, 2. connection between said grid and plate including the whole of the secondary winding of said input couplin transformer, a portion of said inductor co and said fixed condenser, and a connection from said grid to said filament including a variable condenser. 1

8; Radio receiving apparatus com rising eatstone bridge including impedance between two of said electrodes in a balancing arm thereof, impedance between two other of said electrodes in a second balancing arm adjadances connecting another two of said e ectrodes forming the remaining balancing arms of said brid e,

input and ,output circuits for said tube meluded respectivel in conjugate arms ofsaid bridge, and 'impe ance connected between a point of-saidbridge intermediate said last named arms and a point of disturbing potential remote from said input and output circuits. v

9. Radio receivin apparatus com rising a thermionic tube aving a cath e electrode and two other electrodes, a Wheatstone 1 bridge three points of which are connected to said electrodes, and the fourth point of which is. determined by impedances connected be: tween s'aid cathode and one'of said electrodes,

input and output circuits for said tube included respectively in conjugate arms of said :nected to said' cathode and one trodes, and of whose; pair points, one is to the other of said conjugate points and a potential remote from said input and output electrodes, input and output circuits for said tube included respectively-in conjugate arms of said brid e, and impedance connected between the ot er point of said second pair of oint of disturbing circuits.

In testimony whereof I have hereunto affixed my signature .-this 22nd day of July, 1925,

JOHN M.- MILLER;

bridge, and impedance connected'between said fourth point and a-point of disturbing 1 potentialremote :fromsaid inputand output vcircuits.

10. Radio receiving apparatus, comprising thermionic tube having a cathode and two ["other, electrodes, a Wheatstone bridge one pair of conjugate points of which are con q; said, eleco conjugate 

